Impedance matching device and impedance matching method

Abstract

An impedance matching device includes: a variable capacitor in which a plurality of first capacitance elements or a plurality of second capacitance elements are connected in parallel; a calculation unit that calculates an impedance or a reflection coefficient on the load side using information regarding the impedance acquired from the outside; and a control unit that determines an ON/OFF state to be taken by each of semiconductor switches included in the variable capacitor using the impedance or the reflection coefficient calculated by the calculation unit and turns on or off the semiconductor switches included in the first or second capacitance element based on the determined state. The control unit cyclically switches semiconductor switches to be turned on or off in a predetermined order.

What is claimed is: 
     
       1. An impedance matching device for achieving impedance matching between a high frequency power supply and a load, the device comprising:
 a variable capacitor in which a plurality of first capacitance elements are connected in parallel, each of the plurality of capacitance elements including a plurality of series circuits each having a capacitor and a semiconductor switch; 
 a calculation unit coupled to an impedance information detection unit located between the high frequency power supply and the impedance matching device to calculate an impedance information or a reflection coefficient on a load side of the load; and 
 a control unit coupled to the calculation unit to determine an ON/OFF state of the semiconductor switches using the impedance information or the reflection coefficient calculated by the calculation unit to generate control signals to control the semiconductor switches by turning on or off the semiconductor switches, 
 wherein the control signals cyclically switch the semiconductor switches turning on or off the semiconductor switches in a predetermined order until the impedance matching is achieved. 
 
     
     
       2. The impedance matching device according to  claim 1 ,
 wherein the control unit cyclically switches semiconductor switches to be turned on or off each time one semiconductor switch is turned on or off N (N is an integer of 2 or more) times. 
 
     
     
       3. The impedance matching device according to  claim 1 ,
 wherein the control unit cyclically switches semiconductor switches to be turned on or off each time one semiconductor switch is turned on or off for a predetermined time. 
 
     
     
       4. The impedance matching device according to  claim 1 ,
 wherein the plurality of capacitors have the same capacitance, and 
 the control unit controls one semiconductor switch from OFF to ON and then from ON to OFF in a state in which the plurality of semiconductor switches are controlled to be OFF so as to turn on only one of the plurality of semiconductor switches. 
 
     
     
       5. The impedance matching device according to  claim 1 ,
 wherein some or all of the capacitors included in the variable capacitor have stepwise different capacitances. 
 
     
     
       6. The impedance matching device according to  claim 5 ,
 wherein some or all of the capacitance elements have a smaller number of semiconductor switches as a capacitance of the capacitor included in each of the capacitance elements is made larger. 
 
     
     
       7. An impedance matching method for performing impedance matching between a high frequency power supply and a load using a variable capacitor which is provided between the high frequency power supply and the load,
 wherein in the variable capacitor, a plurality of capacitance elements are connected in parallel, each of the plurality of capacitance elements including a plurality of series circuits each having a capacitor and a semiconductor switch, 
 the method comprising: 
 calculating an impedance information or a reflection coefficient on a load side of the load; 
 determining an ON/OFF state of the semiconductor switches using the calculated impedance information or reflection coefficient to generate control signals to control the semiconductor switches by turning on or off the semiconductor switches; and 
 cyclically switching the semiconductor switches by turning on or off the semiconductor switches in a predetermined order until the impedance matching is achieved. 
 
     
     
       8. An impedance matching device for achieving impedance matching between a high frequency power supply and a load, the device comprising:
 a variable capacitor in which a plurality of capacitance elements are connected in parallel, each of the plurality of capacitance elements including a circuit having a capacitor and a plurality of semiconductor switches connected in series or parallel; 
 a calculation unit coupled to an impedance information detection unit located between the high frequency power supply and the impedance matching device to calculate an impedance information or a reflection coefficient on a load side of the load; and 
 a control unit coupled to the calculation unit to determine an ON/OFF state of the semiconductor switches using the impedance information or the reflection coefficient calculated by the calculation unit to generate control signals to control the semiconductor switches by turning on or off the semiconductor switches, 
 wherein the control signals cyclically switch the semiconductor switches by turning on or off the semiconductor switches in a predetermined order until the impedance matching is achieved. 
 
     
     
       9. The impedance matching device according to  claim 8 ,
 wherein the control unit cyclically switches semiconductor switches to be turned on or off each time one semiconductor switch is turned on or off N (N is an integer of 2 or more) times. 
 
     
     
       10. The impedance matching device according to  claim 8 ,
 wherein the control unit cyclically switches semiconductor switches to be turned on or off each time one semiconductor switch is turned on or off for a predetermined time. 
 
     
     
       11. The impedance matching device according to  claim 8 ,
 wherein all of the plurality of semiconductor switches are connected in parallel, and the control unit controls one semiconductor switch from OFF to ON and then from ON to OFF in a state in which the plurality of semiconductor switches are controlled to be OFF so as to turn on only one of the plurality of semiconductor switches. 
 
     
     
       12. The impedance matching device according to  claim 8 ,
 wherein all of the plurality of semiconductor switches are connected in series, and the control unit controls one semiconductor switch from ON to OFF and then from OFF to ON in a state in which the plurality of semiconductor switches are controlled to be ON so as to turn off only one of the plurality of semiconductor switches. 
 
     
     
       13. The impedance matching device according to  claim 8 ,
 wherein some or all of the capacitors included in the variable capacitor have stepwise different capacitances. 
 
     
     
       14. The impedance matching device according to  claim 13 ,
 wherein some or all of the capacitance elements have a smaller number of semiconductor switches as a capacitance of the capacitor included in each of the capacitance elements is made larger. 
 
     
     
       15. An impedance matching method for performing impedance matching between a high frequency power supply and a load using a variable capacitor which is provided between the high frequency power supply and the load,
 wherein in the variable capacitor, a plurality of capacitance elements are connected in parallel, each of the plurality of capacitance elements including a circuit having a capacitor and a plurality of semiconductor switches connected in series or parallel, 
 the method comprising: 
 calculating an impedance information or a reflection coefficient on a load side of the load; 
 determining an ON/OFF state of the semiconductor switches using the calculated impedance information or reflection coefficient to generate control signals to control the semiconductor switches by turning on or off the semiconductor switches; and 
 cyclically switching the semiconductor switches by turning on or off the semiconductor switches in a predetermined order until the impedance matching is achieved.